*Kazuhisa A. Chikita¹, Akio Goto², Jun Okada³, Hideo Oyagi⁴, Takashi Yamaguchi⁵ (1.Arctic Research Center, Hokkaido University, 2.Center for Northeast Asian Studies, Tohoku University , 3.Volcanology Research Department, Meteorological Research Institute, JMA , 4.Faculty of Policy Studies, Nanzan University, 5.Hokkaido Research Organization)

*Shintaro Yamasaki¹, Akio Goto², Nobuo Hirano³, Noriyoshi Tsuchiya³, Tetsuya Matsunaka⁴ (1.Disaster Prevention Research Institute, Kyoto University, 2.Center of Northeast Asian Studies, Tohoku University, 3.Graduate school of Environmental Studies, Tohoku University, 4.Institute of Nature and Environmental Technology, Kanazawa University)